Shelf



FIG. 1 is a top plan view of a shelf, showing our new design;

FIG. 2 is a right side elevational view thereof, the left side elevational view being identical thereto;

FIG. 3 is a front elevational view thereof, the rear elevational view being identical thereoto;

FIG. 4 is a cross-sectional view taknen on plane 4--4 in FIG. 1 showing internal detail thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a shelf, as shown and described. 